Cooling Systems for Devices Arranged in Rows

ABSTRACT

Cooling systems for devices arranged in rows are disclosed. An example cooling system for a datacenter includes a supply air duct to extend lengthwise above a first space between a first row of computers and a second row of computers. The example cooling system further includes a branch air duct attached to the supply air duct to extend downward from the supply air duct into the first space.

RELATED APPLICATIONS

This patent arises from a continuation of U.S. patent application Ser.No. 14/932,676 (now U.S. Pat. No. ______) filed on Nov. 4, 2015, whichis hereby incorporated herein by reference in its entirety.

FIELD OF THE DISCLOSURE

This patent generally pertains to cooling systems and more specificallyto cooling systems for devices arranged in rows.

BACKGROUND

Server-based datacenters, sometimes known as server farms or serverclusters, are a large collection of computers, often at a physicallyremote but network accessible location, that provide clients withexpanded computing capability. The expanded computing capabilitytypically is in the form of data storage, data processing, databasemanagement, file management, and website management.

Each computer of the system usually includes a base or case supporting aset of computer components. Depending on the application, computercomponents may include items such as one or more microprocessors, harddrives, solid state memory devices, routers and power supplies. Moregenerally, there are many types of electronic equipment and/or otherdevices that may emit heat to the surrounding area during operation. Tomaintain such components at a safe operating temperature, the base orcase of each computer or other heat generating device usually includesor is otherwise associated with a cooling fan that forces a current ofenvironmentally controlled air from a front face of the computer orother device, across the components, and out through a back end of thecomputer or other device. In some cases, it is this current of air thatdefines the front and back ends of the computer or other device.

Somewhat resembling books in an open bookshelf, computers at adatacenter may be stacked in rack-like cabinets that are neatly arrangedin rows separated by aisles. The aisles provide manual access to thefront and back ends of the computers. The rows of computers are orientedsuch that each individual aisle is exposed solely to computer fronts orsolely to computer backs. Thus, the front ends of computers in one rowface the front ends of computers in the next row across the aisle. Inthe very next aisle, the back ends of computers on opposite sides ofthat aisle face each other. Aisles of computer fronts are generallycooler than backside aisles due to the computer components heating thecurrent of air developed by the computers' internal cooling fans. Thus,front side cooler aisles are often called “cold aisles,” and back sideaisles are known as “hot aisles.” Each aisle being exposed to onlycomputer fronts or to only computer backs creates an alternatingarrangement of cold aisles and hot aisles. Similar arrangements of othertypes of electronic equipment or other devices that generate heat may beimplemented to cool such devices during operation.

Datacenters usually run nonstop and generate a lot of heat.Consequently, a building air conditioning system is usually needed toprevent the computers from overheating. In the event of a fire, agenerally inert gas system or some other type of fire suppression systemautomatically activates to prevent or reduce (e.g., minimize) damage.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cutaway perspective view of an example datacenter or serverfarm constructed in accordance with the teachings disclosed herein.

FIG. 2 is a cross-sectional end view of the example datacenter shown inFIG. 1.

FIG. 3 is cross-sectional end view similar to FIG. 2 but showing anexample cooling system of the example datacenter constructed inaccordance with the teachings disclosed herein, wherein portions of theexample cooling system are schematically illustrated.

FIG. 4 is cross-sectional end view similar to FIG. 3 but showing exampleair ducts of the example cooling system in a deflated state as opposedto the inflated state shown in FIG. 3.

FIG. 5 is a cross-sectional view taken along line 5-5 of FIG. 3.

FIG. 6 is a cross-sectional view taken along line 6-6 of FIG. 4.

FIG. 7 is a cross-sectional end view of an example supply air ductconstructed in accordance with the teachings disclosed herein.

FIG. 8 is a cross-sectional end view similar to FIG. 7 but showing theexample air duct in a deflated state as opposed to the inflated stateshown in FIG. 7.

FIG. 9 is a cross-sectional view similar to FIG. 3 but showing anotherexample cooling system constructed in accordance with the teachingsdisclosed herein.

FIG. 10 is a cross-sectional view similar to FIG. 9 but showing theexample air ducts in a deflated state as opposed to the inflated stateshown in FIG. 9.

FIG. 11 is a cross-sectional view similar to FIG. 9 but showing anotherexample cooling system constructed in accordance with the teachingsdisclosed herein.

FIG. 12 is a cross-sectional view similar to FIG. 11 but showing theexample air ducts in a deflated state as opposed to the inflated stateshown in FIG. 11.

FIG. 13 is a cross-sectional view similar to FIG. 3 but showing anotherexample cooling system constructed in accordance with the teachingsdisclosed herein.

FIG. 14 is a cross-sectional view taken along line 14-14 of FIG. 13.

FIG. 15 is a cross-sectional view similar to FIG. 13 but showing theexample air ducts in a deflated state as opposed to the inflated stateshown in FIG. 13.

FIG. 16 is a cross-sectional view similar to FIG. 3 but showing anotherexample cooling system constructed in accordance with the teachingsdisclosed herein.

FIG. 17 is a cross-sectional view similar to FIG. 16 but showing just asingle example air duct.

FIG. 18 is a cross-sectional view similar to FIG. 3 but showing anotherexample cooling system constructed in accordance with the teachingsdisclosed herein.

FIG. 19 is a cross-sectional view taken along line 19-19 of FIG. 18.

FIG. 20 is a cross-sectional view similar to FIG. 19 but showing anotherexample cooling system constructed in accordance with the teachingsdisclosed herein.

FIG. 21 is a cross-sectional view similar to FIGS. 19 and 20 but showinganother example cooling system constructed in accordance with theteachings disclosed herein.

FIG. 22 is a cross-sectional view taken along line 22-22 of FIG. 20.

FIG. 23 is a cross-sectional view taken along line 23-23 of FIG. 21.

DETAILED DESCRIPTION

Example cooling systems for server-based datacenters, or server farms,include air permeable inflatable air ducts installed above multiple rowsof computer racks. In some examples, in the event of a fire, the airducts deflate and collapse so as not to obstruct the flow of a fireextinguishing gas. In some examples, when inflated, the air ducts havean expanded shape that inhibits adverse mixing of air between hot aislesand cold aisles. In some examples, wings extend laterally from the airduct to further reduce the mixing of hot and cold air. In some examples,a series of inflatable branch ducts extend downward from a supply airduct to reach well into cold aisles. In some examples, nozzles and/orinternal baffles promote radial air discharge from the supply air duct.

FIGS. 1 and 2 show an example datacenter 10 including a building 12containing a plurality of computers 14 in a plurality of cabinets 16.The term, “computer” refers to any digital processing device, examplesof which include a server, a data storage device, a hard drive, a solidstate memory, etc. The term, “cabinet” refers to any structure forsupporting and/or housing one or more of the plurality of computers 14.Examples of a cabinet include a plurality of enclosures supportingand/or housing at least one computer, a single enclosure containing asingle computer, a single enclosure housing a plurality of computers, arack, a shelf, etc. In examples where a plurality of computers arehoused or supported by or within one or more cabinets, the term, “row ofcomputers” encompasses the associated cabinets (i.e., the racks,shelving, and/or other enclosure or support for the computers). So, insome examples, the terms, “row of computers” and “row of cabinets” canbe used interchangeably. Although the teachings of this disclosure aredescribed with respect to rows of computers, the teachings of thisdisclosure may apply to any other type of electronic equipment ordevices that are to be cooled through forced air when arranged in one ormore rows.

In the illustrated example, the cabinets 16 are arranged in a pluralityof rows 18 to create a first row of computers 18 a (a first row ofcabinets) and a second row of computers 18 b (a second row of cabinets).The plurality of rows of computers 18 also creates an alternatingarrangement of a plurality of cold aisles 20 (e.g., a first aisle 20 a)and a plurality of hot aisles 22 (e.g., a second aisle 22 a and a thirdaisle 22 b). In some examples, there may be only a single hot aisle anda single cold aisle. As used herein, the term “aisle” refers to thespace between adjacent rows of computers 18 as well as the spaceadjacent the outer side of an outer row of the plurality of rows 18.Thus, in some examples, there may be only a single row of computers 18that defines hot and cold aisles on either side without adjacent rows oneither side of the single row of computers 18. The terms, “hot” and“cold” in reference to an aisle merely means that the average airtemperature of the hot aisle is greater than that of the cold aisle. Theterms, “hot aisle” and “cold aisle” do not suggest that either aisle isat any particular absolute temperature. At least one computer 14 and/orat least one row of cabinets 16 define an air passageway 24 between acold aisle 20 a and one or more hot aisles 22 a, 22 b. One or moreinternal fans 25 within the air passageway 24 creates a current of air26 (e.g., a first current of air 26 a from the cold aisle 20 a (thefirst aisle) to the first hot aisle 22 a (the second aisle) and/or asecond current of air 26 b from the cold aisle 20 a to the second hotaisle 22 b (the third aisle)) for cooling the internal components of thecomputers 14. The cabinets 16 have a top surface 28 that is below andspaced apart from an overhead surface 30 of the building 12 to create agap 32 between the top surface 28 and the overhead surface 30.

In the illustrated example, the datacenter 10 also includes a firesuppression system 34. In some examples, the fire suppression system 34includes one or more pressurized tanks 36 of a fire extinguishing fluid38 (FIG. 4) such as halon, halocarbons, carbon dioxide or an inert gas.In the event of a fire-related incident (e.g., fire, heat, smoke,manually triggered fire alarm, etc.), a sensor 40 detects and respondsto the incident by sending a signal 42 that opens a valve 44, whichreleases the fire extinguishing fluid 38 from the tanks 36 to displacethe oxygen surrounding the rows of computers 18.

FIG. 3-6 show the addition of an example cooling system 46 forefficiently extracting heat generated by the computers 14 during normaloperation without interfering with the fire suppression system 34 duringa fire 48 (FIG. 4). In this example, the cooling system 46 includes anair filter 50, a known cooling coil 52 (e.g., a water, glycol, orrefrigerant cooled heat exchanger), a blower system 54, a supply airmanifold 56, at least one branch air duct 58, at least one supply airduct 60, at least one return air register 62, and a return air manifold64. The term, “blower system” refers to one or more blowers 66 poweredby at least one motor 68. The supply air duct 60 is inflatable by virtueof its tubular wall 70 (e.g., 70 a and 70 b) being made of a pliablematerial (e.g. air permeable sheet, air impermeable sheet, nonmetallicsheet, coated fabric, uncoated fabric, and various combinationsthereof). The term, “pliable” refers to a material that can be crumpledand later straightened without appreciable damage to the material. Theterm, “inflatable” as it relates to an air duct means that the duct'sinternal volume expands with internal air pressure and tends to collapsewhen the pressure is removed.

During normal operation, as shown in FIGS. 3 and 5, the blower 66 drawsair 72 from the return air manifold 64, through the filter 50, andthrough the cooling coil 52. The blower 66 then discharges the filteredcool air through the supply air manifold 56, through the branch airducts 58 and into an axial end 74 of each supply air duct 60. In theillustrated example, the discharge pressure of blower 66 inflates orfully expands each supply air duct 60. The supply air duct 60 in itsexpanded state, as shown in the examples of FIGS. 3 and 5, creates anobstruction that substantially fills or blocks gap 32 between the topsurface 28 and the overhead surface 30. In some examples, the supply airduct 60 spans the entire gap 32 so as to be in contact with both the topsurface 28 and the overhead surface 30 when inflated. The supply airduct 60 blocking the gap 32 reduces (e.g., minimizes) the mixing of coldand warm air between the cold aisle 20 a and the hot aisle 22 a.

In this example, each supply air duct 60 has an air permeable sidewall70 a facing the cold aisle 20 a and a substantially impermeable oppositesidewall 70 b facing the hot aisle 22 a. The sidewall 70 a is madepermeable by any suitable means, examples of which include porosity inthe material of the tubular wall 70 a, perforations in the tubular wall70 a, and/or the sidewall 70 a having one or more nozzles 76 (FIGS. 18and 19). In examples where only the sidewall 70 a is air permeable, airdischarged from the blower 66 flows lengthwise 78 (FIG. 5) through thesupply air duct 60, radially outward through the sidewall 70 a, anddownward into the cold aisle 20 a. From the cold aisle 20 a, the coolair flows through the computers 14 via an air passageway 80 (through thecomputers 14 and/or through the cabinets 16), into the hot aisle 22 a,and downward toward the return register 62. The register 62 conveys theair from the hot aisle 22 a into the return manifold 64, which returnsthe air back to the filter 50 for recirculation.

In some examples, in the event of a fire 48 or a fire-related incident(e.g., flame, smoke, heat, manually triggered fire alarm, etc.), thesensor 40 responds by sending the signal 42 to activate the firesuppression system 34, as described earlier, and also sends a signal 82that de-energizes the motor 68 and, thus, stops the blower 66. Stoppingthe blower 66 depressurizes the supply air duct 60, which causes thesupply air duct 60 to collapse to its deflated state, as shown in FIGS.4 and 6. In the deflated state, the collapsed supply air duct 60 opensor substantially unblocks the gap 32 so that the fire extinguishingfluid 38 in a gaseous state can readily disperse over, around andthrough the multiple rows of computers 18.

In some examples, the cooling system 46 includes means for preventing acollapsed supply air duct 60 from drooping excessively over the sides ofthe cabinets 16 and/or the computers 14. In the example shown in FIGS. 7and 8, for instance, an internal restraint 84 (e.g., a string, a strap,a cable, a chain, a horizontal sheet, an elastic cord, a tie rod, etc.)limits the radially outward movement of the sidewalls 70 a and 70 b asthe supply air ducts 60 deflate. FIG. 7 shows the supply air duct 60 inits inflated state, and FIG. 8 shows the supply air duct 60 in itsdeflated state. In some examples, a pair of taut internal or externalrestraints (e.g., cables) running parallel to the supply air duct 60extend along the entire length of the sidewalls 70 a and 70 b. In someexamples, the supply air duct 60 rests upon the top surface 28 such thatthe weight of the supply air duct is supported by the top surface 28. Insome examples, the supply air duct 60 is secured to the top surface 28to prevent the supply air duct 60 from sliding off the edge of the topsurface 28 of the cabinets 16. In some examples, a bottom 86 of thesupply air duct 60 rests upon a basket (not shown) rather than directlyon the top surface 28 of the cabinets 16, wherein the basket is widerthan the top surface 28 of the cabinets 16.

FIGS. 9 and 10 show an example cooling system 88 with a supply air duct90 installed lengthwise (i.e., duct 90 is elongate in a directionparallel to the aisles) over the first cold aisle 20 a, between the rowsof computer 18 a and 18 b. In some examples, the supply air duct 90 hasa pliable tubular wall 92 that renders the duct 90 inflatable, so theduct 90 has selectively an inflated state (FIG. 9) and a deflated state(FIG. 10). In the illustrated example, the supply air duct 90 has an airpermeable lower section 94 for delivering cool supply air into the coldaisle 20 a.

To prevent or reduce mixing of air between cold and hot aisles, thesupply air duct 90 has an air impermeable upper section 95 and at leastone wing 96 (e.g., a first wing 96 a and a second wing 96 b) extendingfrom the supply air duct 90 toward an adjacent row of computers 18. Inthe illustrated example, the first wing 96 a extends laterally from thesupply air duct 90 to a first top surface 28 of the first row ofcomputers 18 a (and/or its associated cabinet 16), and the second wing96 b extends to a second top surface 28 of the second row of computers18 b (and/or its associated cabinet 16). In some examples, the wings 96extend lengthwise substantially the full length of the rows of computer18 and are made of a pliable sheet of material held taut by havingdistal edges 98 a, 98 b fastened to the cabinets 16 of the computer rows18.

In some examples, the supply air duct 90 is installed at each coldaisle, so when the blower 66 is activated during normal operation, afirst supply current of air 100 flows sequentially from the second aisle22 a (the first hot aisle), through the return register 62, through thereturn air manifold 64, through the filter 50, through the cooling coil52, through the blower 66, through the supply air manifold 56,lengthwise through the first supply air duct 90, and downward from thefirst supply air duct 90 into the first aisle 20 a (the cold aisle).Further, in the illustrated example, a second supply current of air 102flows sequentially from the third aisle 22 b (the second hot aisle),through the return register 62, through the return air manifold 64,through the filter 50, through the cooling coil 52, through the blower66, through the supply air manifold 56, lengthwise through the supplyair duct 90, and downward from the supply air duct 90 into the firstaisle 20 a (the cold aisle). The relatively cool air in the first aisle20 a supplies a first current of air 26 a flowing through the first rowof computers 18 a to the second aisle 22 a and further supplies a secondcurrent of air 26 b flowing through the second row of computers 18 b tothe third aisle 22 b.

In the event of a fire-related incident, the sensor 40 deactivates theblower 66 in some examples, which causes the supply air duct 90 tocollapse to its deflated state, as shown in FIG. 10. In the deflatedstate, the collapsed supply air duct 90 opens or unblocks the gap 32 tofacilitate the dispersion of the fire extinguishing fluid 38.

FIGS. 11 and 12 show an example cooling system 108 that is similar tothe system 88 of FIGS. 9 and 10. With the cooling system 108, however,the supply air duct 90 is elevated to place the wings 96 above andspaced apart from the computer rows 18. The vertical spacing furtherfacilitates the dispersion of the fire extinguishing fluid 38 whenneeded while reducing the amount of warm air above the supply air duct90 (e.g., above the wings 96) from being entrained by the cooler airdispersed from the bottom of the supply air duct 90 (e.g., below thewings 96) into the cold aisle. FIG. 11 shows the supply air duct 90 inits inflated state, and FIG. 12 shows the supply air duct 90 in itsdeflated state. In some examples, the wing 96 extends lengthwisesubstantially the full length of the rows of computer 18 and is made ofa pliable sheet of material. The supply air duct 90 can be supported andthe wings 96 can be held taut by any suitable means, such as by a tautcable, a track, struts, and/or combinations thereof.

FIGS. 13-15 show an example cooling system 110 that provides a moreconcentrated discharge of cool supply air directly in the cold aisles20, thereby reducing (e.g., minimizing) the mixing of cool air withwarmer air in the hot aisles 22. In the illustrated example, a supplyair duct 112 with a plurality of branch air ducts 114 are installed ineach cold aisle 20. FIGS. 13 and 14 show at least one of the air ductsin an inflated state, and FIG. 15 shows at least one of them in adeflated state. The supply air duct 112 is elevated with an uppersection 116 that is higher than the top surface 28 of the rows ofcomputer 18 to provide head clearance for personnel in the area and tofacilitate the dispersion of the fire extinguishing fluid 38 whenneeded.

To ensure that the branch air ducts 114 inject cool air well into thecold aisle 20, a lowermost distal point 118 of the branch air duct 114extends lower than the top surface 28 of the computer rows 18, and thedistal point 118 lies within a certain row length 120 of the row ofcomputers 18. That is, the distal point 118 is positioned within alength of the cold aisle 20 defined by ends of the row of computers 18.The branch air ducts 114 include an air permeable tubular wall 122 madeof a pliable material so that personnel working in the aisle can simplyshove branch air ducts aside to gain unobstructed access to thecomputers 14.

During normal operation, as shown in the illustrated examples of FIGS.13 and 14, a main current of air 124 flows sequentially from the secondaisle 22 a (the first hot aisle), through the return air register 62,through the return air manifold 64, through the filter 50, through thecooling coil 52, through the blower 66, through the supply air manifold126, into the supply air duct 112, lengthwise through the supply airduct 112, downward from the supply air duct 112 through the branch airducts 114, and outward from the branch air ducts 114 into the firstaisle 20 a (the cold aisle). The main current of air 124 in the firstaisle 20 a supplies a first current of air 26 a through the first row ofcomputers 18 a and a second current of air 26 b through the second rowof computers 18 b.

FIGS. 16 and 17 show an example cooling system 128 that has an air duct130 (e.g., air duct 130 a and 130 b) atop each row of computers 18,wherein the air duct 130 has a longitudinal internal web 132 (e.g.,first web 132 a in the first air duct 130 a and second web 132 b in thesecond air duct 130 b) that separates each air duct 130 into a supplychamber 134 (e.g., 134 a and 134 b) and a return chamber 136 (e.g., 136a and 136 b). The air duct 130 has a pliable tubular wall 138 that isair permeable to pass air from the hot aisle 22 a into the returnchamber 136 and to release air from the supply chamber 134 to the coldaisle 20 a. The blower 66 and the internal fans 25 drive the movement ofair. To reduce the likelihood of the negative pressure in the returnchamber 136 causing the air duct's pliable tubular wall to collapse, theair duct 130 includes some form of framework 140 that holds the air duct130 in an expanded shape. Examples of the framework 140 include aplurality of rigid hoops, a longitudinal tensioning device, andcombinations thereof.

In the illustrated example, the first row of computers 18 a is betweenthe first aisle 20 a (the cold aisle) and the second aisle 22 a (thefirst hot aisle), and the second row of computers 18 b is between thefirst aisle 20 a (the cold aisle) and the third aisle 22 b (the secondhot aisle). In this example, the cooling system 128 includes the firstair duct 130 a atop the first row of computers 18 a, the second air duct130 b atop the second row of computers 18 b, the first web 132 adividing the first air duct 130 a into a first return chamber 136 a anda first supply chamber 134 a, the second web 132 b dividing second theair duct 130 b into a second return chamber 136 b and a second supplychamber 134 b, the blower system 54, a first fan 25 a for urging a firstcurrent of air 26 a through the first row of computers 18 a, and asecond fan 25 b for urging a second current of air 26 b through thesecond row of computers 18 b.

During normal operation of the example cooling system 128, the blowersystem 54 draws air from the second aisle 22 a (the first hot aisle)into the first return chamber 136 a, the blower system 54 urges air fromthe first return chamber 136 a into the first supply chamber 134 a via anetwork of air ducts 142, and the blower system 54 urges air from thefirst supply chamber 134 a into the first aisle 20 a (the cold aisle).Similarly, in the illustrated example, the blower system 54 draws airfrom the third aisle 22 b (the second hot aisle) into the second returnchamber 136 b, the blower system 54 urges air from the second returnchamber 136 b into the second supply chamber 134 b via the air ducts142, and the blower system 54 urges air from the second supply chamber134 b into the first aisle 20 a (the cold aisle).

FIGS. 18 and 19 show an example adjustable or fixed-position nozzle 76that can be used to direct a main current of air 144 discharged from thenozzle. Further, the example nozzle 76 can also be used for inducingsurrounding air currents 146 to flow in the same general direction asthe main current of air 144. In some examples, the surrounding aircurrents 146 are from the air released through the air permeablesidewall of a pliable air duct in the area surrounding the nozzle 76.The nozzle 76 and the principle of inducing and directing surroundingair currents can be applied to any of the air duct examples shown inFIGS. 3-23.

FIGS. 20-23 show example internal baffles 198, 200 that can be used toreduce negative effects that might otherwise result due to the dynamicair pressure of unrestricted air rushing axially through a supply airduct 202, 204. For instance, without the baffles 198, 200, air releasedthrough the air permeable sidewall of the ducts 202, 204 might tend tofollow the axial longitudinal direction of the air flowing lengthwisethrough the duct rather than discharging from the duct in an often moredesirable radial direction (perpendicular to the duct's length). In theillustrated example, the internal baffles 198, 200 interrupt the axialor longitudinal velocity of the air entering axial at the end 74 of thecorresponding supply air ducts 202, 204. The internal baffles 198, 200may be applied to any of the air duct examples shown in FIGS. 3-23.

In the example shown in FIGS. 20 and 22, the supply air duct 202includes an air permeable pliable outer wall 206 and the internal baffle198 that is horizontally elongate. In this example, the internal baffle198 is tubular (e.g., conical or cylindrical). In the illustratedexample, the internal baffle 198 separates an interior space of thesupply air duct 202 into an inner upstream chamber 208 and an outerdownstream chamber 210. A supply current of air 212 flows sequentiallyfrom the second aisle 22 a (a hot aisle) through a cooling system,lengthwise through the upstream chamber 208, radially outward throughthe internal baffle 198, through the downstream chamber 210, radiallyoutward through an air permeable pliable outer wall 214 of the supplyair duct 202, and downward from the supply air duct 202 into the firstaisle 20 a (a cold aisle). The air may then pass through the row ofcomputers 18 a and into second aisle 22 a (the hot aisle). In someexamples, the cooling system includes the return register 62, the blowersystem 54, and suitable ductwork to return the air back to the upstreamchamber 208 at the axial end 74 of the supply air duct 202 to repeat thecircuit.

In the example shown in FIGS. 21 and 23, the supply air duct 204includes an air permeable pliable outer wall 216 and the internal baffle200 that is horizontally elongate. In this example, the internal baffle200 is generally planar. In the illustrated examples, the internalbaffle 200 separates an interior space of supply air duct 204 into aninner upstream chamber 218 and an outer downstream chamber 220. A supplycurrent of air 212 flows sequentially from the second aisle 22 a (a hotaisle) through a cooling system, lengthwise through the upstream chamber218, radially outward through the internal baffle 200, through thedownstream chamber 220, radially outward through an air permeablepliable outer wall 222 of the supply air duct 204, and downward from thesupply air duct 204 into the first aisle 20 a (cold aisle). The air maythen pass through the row of computers 18 a and into second aisle 22 a(the hot aisle). In some examples, the cooling system includes thereturn register 62, the blower system 54, and suitable ductwork toreturn the air back to the upstream chamber 218 at the axial end 74 torepeat the circuit.

Although certain example methods, apparatus and articles of manufacturehave been described herein, the scope of the coverage of this patent isnot limited thereto. On the contrary, this patent covers all methods,apparatus and articles of manufacture fairly falling within the scope ofthe appended claims either literally or under the doctrine ofequivalents.

What is claimed is:
 1. A cooling system for a datacenter, the coolingsystem comprising: a supply air duct to extend lengthwise above a firstspace between a first row of computers and a second row of computers;and a branch air duct attached to the supply air duct to extend downwardfrom the supply air duct into the first space.
 2. The cooling system ofclaim 1, wherein the first row of computers is to provide passage of afirst current of air from the first space to a second space on anopposite side of the first row of computers, and the second row ofcomputers is to provide passage of a second current of air from thefirst space to a third space on the opposite side of the second row ofcomputers.
 3. The cooling system of claim 2, wherein the branch air ductis to be situated within a distance defined by opposite ends of thefirst row of computers.
 4. The cooling system of claim 3, wherein thebranch air duct is a first branch air duct, the cooling system furtherincluding a second branch air duct that is spaced apart from the firstbranch air duct, the second branch air duct situated within the distancedefined by opposite ends of the first row of computers.
 5. The coolingsystem of claim 1, wherein the branch air duct includes a tubular wallformed of a pliable material that enables the branch air duct to bemanually moved during normal operation.
 6. The cooling system of claim1, further including a sensor responsive to at least one of a fire, atemperature limit, or a presence of smoke, at least one of the supplyair duct or the branch air duct to change from an inflated state to adeflated state in response to the sensor detecting the fire, thetemperature limit, or the presence of smoke.
 7. The cooling system ofclaim 1, wherein a portion of the supply air duct is higher than a topsurface associated with the first row of computers.
 8. The coolingsystem of claim 1, wherein a distal point of the branch air duct is tobe higher than a bottom of the first row of computers.
 9. The coolingsystem of claim 1, wherein a junction between the supply air duct andthe branch air duct is higher than a top surface associated with thefirst row of computers.
 10. A cooling system for a datacenter in abuilding, the cooling system comprising: a supply air duct to extendlengthwise along a first aisle within the building, the first aisledefined between a first row of computers and a second row of computers,the first row of computers to provide passage of a first current of airfrom the first aisle to a second aisle on an opposite side of the firstrow of computers, the second row of computers to provide passage of asecond current of air from the first aisle to a third aisle on anopposite side of the second row of computers, the supply air duct to bepositioned with an upper section that is higher than a top surfaceassociated with the first and second rows of computers; and a pluralityof branch air ducts extending downward from the supply air duct, each ofthe plurality of branch air ducts extending to a distal point that islower than the top surface associated with the first and second rows ofcomputers, the distal point being situated between the first row ofcomputers and the second row of computers, the cooling system to force amain current of air sequentially from the second aisle, lengthwisethrough the supply air duct, downward from the supply air duct throughthe plurality of branch air ducts, and outward from the plurality ofbranch air ducts into the first aisle, the main current of air being asource for the first current of air and the second current of air. 11.The cooling system of claim 10, wherein the distal point of each of theplurality of branch air ducts is to be positioned within a length of thefirst aisle defined by ends of the first row of computers.
 12. Thecooling system of claim 10, wherein a branch air duct of the pluralityof branch air ducts includes a pliable tubular wall that renders thebranch air duct selectively inflatable.
 13. The cooling system of claim10, wherein a branch air duct of the plurality of branch air ductsincludes an air permeable pliable tubular wall that renders the branchair duct selectively inflatable.
 14. The cooling system of claim 10,wherein the supply air duct includes a pliable tubular wall that rendersthe supply air duct selectively inflatable.
 15. The cooling system ofclaim 10, further including a sensor to be disposed within the building,the sensor to be responsive to at least one of a fire, a temperaturelimit, or a presence of smoke, at least one of the supply air duct orthe plurality of branch air ducts changing from an inflated state to adeflated state in response to the sensor detecting the at least one ofthe fire, the temperature limit, or the presence of smoke.
 16. Thecooling system of claim 10, wherein the first aisle is cooler than thesecond aisle.
 17. A cooling system comprising: a supply air ductincluding a first tubular wall, the supply air duct extending along anaisle between a first row of computers and a second row of computers;and a branch air duct including a second tubular wall extending downwardfrom the supply air duct into the aisle, the branch air duct having aninflated state and a deflated state, the branch air duct having a lengthin a downward direction from the supply air duct that is less than anoverall length of the supply air duct.
 18. The cooling system of claim17, further including a plurality of branch air ducts to extend downwardfrom the supply air duct, the plurality of branch air ducts distributedalong a length of the aisle between ends of the first row of computers.19. The cooling system of claim 18, wherein the aisle is a first aisle,the cooling system to force a main current of air sequentially from asecond aisle, through a cooling coil, through the supply air duct,downward from the supply air duct through the branch air duct, andoutward from the branch air duct into the first aisle.
 20. The coolingsystem of claim 18, wherein the branch air duct extends to a distalpoint that is lower than a top surface associated with the first row ofcomputers and higher than a bottom surface associated with the first rowof computers.